1. Field of the Invention
The invention relates to mechanisms for mounting ground engaging wheels to mower decks for supporting the mower decks above the ground.
2. Description of the Prior Art
It is known to provide mowing devices with mower decks carried by wheels. Wheels referred to as gage wheels are attached to the decks for engaging the ground such that the deck can roll over the ground to yield a predetermined height of cut. Wheels are also provided on portions of the deck for engaging the ground when that portion of the deck encounters an irregularity such as a bump in the ground conditions. These wheels, called anti-scalp wheels, allow the deck to ride over the bump and thereby prevent vegetation from being scalped or cut at a height less than the predetermined height when irregularities or bumps are encountered.
Many conventional gage and anti-scalp wheels provide a mounting arm attached to the deck and an axle carried by the mounting arm. The wheel is carried for rotation on the axle. As the wheel rolls straight ahead over the ground it encounters radial loads. The wheel is subjected to axial loads, or forces having direction parallel to the axis of the axle, as the wheel rolls over the ground during a turn. These axial forces are transmitted from the wheel to the mounting arm, or from the wheel to the axle to the mounting arm. Various mechanisms have been developed to attach these wheels to the mounting arm such that the axial forces are properly transmitted to the mounting arm.
One type of prior art wheel mounting provides a mounting arm attached to the deck. A bolt acts as an axle and is carried by the mounting arm. The wheel is rotatably mounted directly on the bolt. A washer is positioned on the bolt between the wheel and the mounting arm. The wheel transfers the above described axial loads to the washer, which in turn transfers the forces to the mounting arm. Similarly, the wheel can transfer axial loads in the other direction to the head of the bolt, which in turn transfers the force through the longitudinal portion of the bolt to the mounting arm. However, the surfaces of contact between the wheel and the washer, and between the wheel and the bolt head are exposed to the dirt and debris of the mower's environment. Dirt and debris can therefore get caught between the contacting surfaces and cause the parts to wear as the parts rub against each other during operation. Clearance between the parts is created as the parts wear, which causes the wheel to wobble during operation. Noise is thereby created and precision is lost in the adjustment of the height of cut.
A second type of conventional mounting device provides a mounting arm through which a bolt is carried. A sleeve rotates on the bolt and is fixed for rotation with the wheel. A washer is positioned on the bolt between the sleeve and the mounting arm. Axial forces are transmitted from the wheel to the sleeve, which in turn presses against the washer. The washer then transfers this force to the mounting arm. This type of mounting is similarly prone to the entrance of dirt between the contacting surfaces of the sleeve, washer, and mounting arm. Similarly, dirt may enter between the contacting surface between the sleeve and the head of the bolt. This entrance of dirt can cause wear, noise, and loss of fine adjustment as described above.
A third type of conventional mounting provides a mounting arm and an axle bolt. Metal sleeves or bearings are carried on the bolt. A tube is fitted over the sleeves or bearings and is fixed for rotation with the wheel. Grease seals are positioned on each side of the wheel and form a seal between the tube and the axle. Lubricant can thereby be kept between the seals to lubricate the metal sleeves or bearings during operation. The tube extends outwardly from the seals to abut a washer positioned against the mounting arm. The wheel transfers axial forces through the tube to the washer, which further transfers the force to the mounting arm. At the end of the axle opposite the mounting arm a washer is positioned between the tube and a pin carried by the axle. Axial forces can also be transferred through the tube to this washer and pin. The axle then transfers the load to the mounting arm. This wheel mounting device can allow dirt and debris to enter between the contacting surfaces of the tube and washer. Wear can result, which can cause wobble, noise, and loss of fine adjustment of mower height. The resulting wobble can also cause the bearings to become damaged or non-operational.